Classification of silicosis is made according to the disease's severity (including radiographic pattern), onset, and rapidity of progression. These include:

- Chronic simple silicosis: Usually resulting from long-term exposure (10 years or more) to relatively low concentrations of silica dust and usually appearing 10–30 years after first exposure. This is the most common type of silicosis. Patients with this type of silicosis, especially early on, may not have obvious signs or symptoms of disease, but abnormalities may be detected by x-ray. Chronic cough and exertional dyspnea (shortness of breath) are common findings. Radiographically, chronic simple silicosis reveals a profusion of small (<10 mm in diameter) opacities, typically rounded, and predominating in the upper lung zones.

- Accelerated silicosis: Silicosis that develops 5–10 years after first exposure to higher concentrations of silica dust. Symptoms and x-ray findings are similar to chronic simple silicosis, but occur earlier and tend to progress more rapidly. Patients with accelerated silicosis are at greater risk for complicated disease, including progressive massive fibrosis (PMF).

- Complicated silicosis: Silicosis can become "complicated" by the development of severe scarring (progressive massive fibrosis, or also known as conglomerate silicosis), where the small nodules gradually become confluent, reaching a size of 1 cm or greater. PMF is associated with more severe symptoms and respiratory impairment than simple disease. Silicosis can also be complicated by other lung disease, such as tuberculosis, non-tuberculous mycobacterial infection, and fungal infection, certain autoimmune diseases, and lung cancer. Complicated silicosis is more common with accelerated silicosis than with the chronic variety.

- Acute silicosis: Silicosis that develops a few weeks to 5 years after exposure to high concentrations of respirable silica dust. This is also known as silicoproteinosis. Symptoms of acute silicosis include more rapid onset of severe disabling shortness of breath, cough, weakness, and weight loss, often leading to death. The x-ray usually reveals a diffuse alveolar filling with air bronchograms, described as a ground-glass appearance, and similar to pneumonia, pulmonary edema, alveolar hemorrhage, and alveolar cell lung cancer.

Brown lung can ultimately result in narrowing of the airways, lung scarring and death from infection or respiratory failure.

Occupational lung diseases are occupational diseases affecting the respiratory system, including occupational asthma, black lung disease (coalworker's pneumoconiosis), chronic obstructive pulmonary disease (COPD), mesothelioma, and silicosis. Infectious lung diseases can also be acquired in an occupational context. Exposure to substances like flock and silica can cause fibrosing lung disease, whereas exposure to carcinogens like asbestos and beryllium can cause lung cancer. Occupational cases of interstitial lung disease may be misdiagnosed as COPD, idiopathic pulmonary fibrosis, or a myriad of other diseases; leading to a delay in identification of the causative agent.

Some symptoms and signs of Bagassosis include breathlessness, cough, haemoptysis, slight fever. Acute diffuse bronchiolitis may also occur. An xray may show mottling of lungs or a shadow.

Mineral dust airway disease is due to inhaled mineral dust causing fibrosis and narrowing of primarily the respiratory bronchioles. It is distinct from pneumoconiosis which is due to lung tissue fibrosis but shares the same cause.

Coal workers' pneumoconiosis (CWP), also known as black lung disease or black lung, is caused by long exposure to coal dust. It is common in coal miners and others who work with coal. It is similar to both silicosis from inhaling silica dust and to the long-term effects of tobacco smoking. Inhaled coal dust progressively builds up in the lungs and cannot be removed by the body; this leads to inflammation, fibrosis, and in worse cases, necrosis.

Coal workers' pneumoconiosis, severe state, develops after the initial, milder form of the disease known as anthracosis ("anthrac" — coal, carbon). This is often asymptomatic and is found to at least some extent in all urban dwellers due to air pollution. Prolonged exposure to large amounts of coal dust can result in more serious forms of the disease, "simple coal workers' pneumoconiosis" and "complicated coal workers' pneumoconiosis" (or progressive massive fibrosis, or PMF). More commonly, workers exposed to coal dust develop industrial bronchitis, clinically defined as chronic bronchitis (i.e. productive cough for 3 months per year for at least 2 years) associated with workplace dust exposure. The incidence of industrial bronchitis varies with age, job, exposure, and smoking. In nonsmokers (who are less prone to develop bronchitis than smokers), studies of coal miners have shown a 16% to 17% incidence of industrial bronchitis.

In 2013 CWP resulted in 25,000 deaths down from 29,000 deaths in 1990.

Byssinosis, also called "brown lung disease" or "Monday fever", is an occupational lung disease caused by exposure to cotton dust in inadequately ventilated working environments. Byssinosis commonly occurs in workers who are employed in yarn and fabric manufacture industries. It is now thought that the cotton dust directly causes the disease and some believe that the causative agents are endotoxins that come from the cell walls of gram-negative bacteria that grow on the cotton. Although bacterial endotoxin is a likely cause, the absence of similar symptoms in workers in other industries exposed to endotoxins makes this uncertain.

Of the 81 byssinosis-related fatalities reported in the United States between 1990 and 1999, 48% included an occupation in the yarn, thread, and fabric industry on the victim's death certificate. This disease often occurred in the times of the industrial revolution. Most commonly young girls working in mills or other textile factories would be afflicted with this disease. In the United States, from 1996 to 2005, North Carolina accounted for about 37% of all deaths caused by byssinosis, with 31, followed by South Carolina (8) and Georgia (7).

The term "brown lung" is a misnomer, as the lungs of affected individuals are not brown.

Asbestosis is a fibrosing interstitial lung disease caused by exposure to forms of the mineral asbestos.

Feline asthma occurs with the inflammation of the small passageways of a cat’s lungs, during the attack the lungs will thicken and constrict making it difficult to breathe. Mucus may be released by the lungs into the airway resulting in fits of coughing and wheezing. Some cats experience a less severe version of an asthma attack and only endure some slight coughing. The obvious signs that a cat is having a respiratory attack are: coughing, wheezing, blue lips and gums, squatting with shoulders hunched and neck extended, rapid open mouth breathing or gasping for air, gagging up foamy mucus and overall weakness.

Positive indications on patient assessment:

- Shortness of breath

- Chest X-ray may show a characteristic patchy, subpleural, bibasilar interstitial infiltrates or small cystic radiolucencies called honeycombing.

Pneumoconiosis in combination with multiple pulmonary rheumatoid nodules in rheumatoid arthritis patients is known as Caplan's syndrome.

Bagassosis has been shown to be due to a thermophilic actinomycetes for which the name thermoactinomycetes sacchari was suggested.

Silicosis (also known as pneumonoultramicroscopicsilicovolcanoconiosis, previously miner's phthisis, grinder's asthma, potter's rot and other occupation-related names) is a form of occupational lung disease caused by inhalation of crystalline silica dust, and is marked by inflammation and scarring in the form of nodular lesions in the upper lobes of the lungs. It is a type of pneumoconiosis.

Silicosis (particularly the acute form) is characterized by shortness of breath, cough, fever, and cyanosis (bluish skin). It may often be misdiagnosed as pulmonary edema (fluid in the lungs), pneumonia, or tuberculosis.

Silicosis resulted in 46,000 deaths globally in 2013 down from 55,000 deaths in 1990.

The name "silicosis" (from the Latin "silex", or flint) was originally used in 1870 by Achille Visconti (1836–1911), prosector in the Ospedale Maggiore of Milan. The recognition of respiratory problems from breathing in dust dates to ancient Greeks and Romans. Agricola, in the mid-16th century, wrote about lung problems from dust inhalation in miners. In 1713, Bernardino Ramazzini noted asthmatic symptoms and sand-like substances in the lungs of stone cutters. With industrialization, as opposed to hand tools, came increased production of dust. The pneumatic hammer drill was introduced in 1897 and sandblasting was introduced in about 1904, both significantly contributing to the increased prevalence of silicosis.

Pneumoconiosis is an occupational lung disease and a restrictive lung disease caused by the inhalation of dust, often in mines and from agriculture.

In 2013, it resulted in 260,000 deaths, up from 251,000 deaths in 1990. Of these deaths, 46,000 were due to silicosis, 24,000 due to asbestosis and 25,000 due to coal workers pneumoconiosis.

Shortness of breath is often the symptom that most bothers people. It is commonly described as: "my breathing requires effort," "I feel out of breath," or "I can't get enough air in". Different terms, however, may be used in different cultures. Typically the shortness of breath is worse on exertion of a prolonged duration and worsens over time. In the advanced stages, or end stage pulmonary disease it occurs during rest and may be always present. It is a source of both anxiety and a poor quality of life in those with COPD. Many people with more advanced COPD breathe through pursed lips and this action can improve shortness of breath in some.

A chronic cough is often the first symptom to develop. When it persists for more than three months each year for at least two years, in combination with sputum production and without another explanation, it is by definition chronic bronchitis. This condition can occur before COPD fully develops. The amount of sputum produced can change over hours to days. In some cases, the cough may not be present or may only occur occasionally and may not be productive. Some people with COPD attribute the symptoms to a "smoker's cough". Sputum may be swallowed or spat out, depending often on social and cultural factors. Vigorous coughing may lead to rib fractures or a brief loss of consciousness. Those with COPD often have a history of "common colds" that last a long time.

The signs and symptoms of asbestosis typically manifest after a significant amount of time has passed following asbestos exposure, often several decades under current conditions in the US. The primary symptom of asbestosis is generally the slow onset of shortness of breath, especially with physical activity. Clinically advanced cases of asbestosis may lead to respiratory failure. When a physician listens with a stethoscope to the lungs of a person with asbestosis, they may hear inspiratory crackles.

The characteristic pulmonary function finding in asbestosis is a restrictive ventilatory defect. This manifests as a reduction in lung volumes, particularly the vital capacity (VC) and total lung capacity (TLC). The TLC may be reduced through alveolar wall thickening; however, this is not always the case. Large airway function, as reflected by FEV/FVC, is generally well preserved. In severe cases, the drastic reduction in lung function due to the stiffening of the lungs and reduced TLC may induce right-sided heart failure (cor pulmonale). In addition to a restrictive defect, asbestosis may produce reduction in diffusion capacity and a low amount of oxygen in the blood of the arteries.

Owners often notice their cat coughing several times per day. Cat coughing sounds different from human coughing, usually sounding more like the cat is passing a hairball. Veterinarians will classify the severity of feline asthma based on the medical signs. There are a number of diseases that are very closely related to feline asthma which must be ruled out before asthma can be diagnosed. Lungworms, heartworms, upper and lower respiratory infections, lung cancer, cardiomyopathy and lymphocytic plasmacytic stomatitis all mimic asthmatic symptoms. Medical signs, pulmonary radiographs, and a positive response to steroids help confirm the diagnosis.

While radiographs can be helpful for diagnosis, airway sampling through transtracheal wash or bronchoalveolar lavage is often necessary. More recently, computed tomography has been found to be more readily available and accurate in distinguishing feline tracheobronchitis from bronchopneumonia.

Oral ingestion of hydrocarbons often is associated with symptoms of mucous membrane irritation, vomiting, and central nervous system depression. Cyanosis, tachycardia, and tachypnea may appear as a result of aspiration, with subsequent development of chemical pneumonitis. Other clinical findings include albuminuria, hematuria, hepatic enzyme derangement, and cardiac arrhythmias. Doses as low as 10 ml orally have been reported to be potentially fatal, whereas some patients have survived the ingestion of 60 ml of petroleum distillates. A history of coughing or choking in association with vomiting strongly suggests aspiration and hydrocarbon pneumonia. Hydrocarbon pneumonia is an acute hemorrhagic necrotizing disease that can develop within 24 h after the ingestion. Pneumonia may require several weeks for complete resolution.

Symptoms of chemical (hydrocarbon) pneumonia may include:

- burning of the nose, eyes, lips, mouth, and throat

- dry cough

- wet cough producing clear, yellow, or green mucus

- cough producing blood or frothy pink matter

- nausea or abdominal pain

- chest pain

- shortness of breath

- painful breathing or pleuritis (an inflammation of the outside covering of the lungs)

- headache

- flu symptoms

Dust pneumonia describes disorders caused by excessive exposure to dust storms, particularly during the Dust Bowl in the United States. A form of pneumonia, dust pneumonia results when the lungs are filled with dust, inflaming the alveoli.

Symptoms of dust pneumonia include high fever, chest pain, difficulty in breathing, and coughing. With dust pneumonia, dust settles all the way into the alveoli of the lungs, stopping the cilia from moving and preventing the lungs from ever clearing themselves.

People who had dust pneumonia often died. There are no official death rates published for the Great Plains in the 1930s. In 1935, dozens of people died in Kansas from dust pneumonia. Red Cross volunteers made and distributed thousands of dust masks, although some farmers and other people in the affected areas refused to wear them.

Occupational asthma is an occupational lung disease and a type of asthma. Like other types of asthma, it is characterized by airway inflammation, reversible airways obstruction, and bronchospasm, but it is caused by something in the workplace environment.

Symptoms include shortness of breath, tightness of the chest, nasal irritation, coughing and wheezing. The first person to use it in reference to a medical condition was Hippocrates, and he believed that tailors, anglers and metalworkers were more likely to be affected by the disease. Although much research has been done since, the inflammatory component of asthma was recognized only in the 1960s.

Hypersensitivity pneumonitis is a related condition, with many occupational examples (e.g. flock worker's lung, farmer's lung, and indium lung). However, although overlapping in many cases, hypersensitivity pneumonitis may be distinguished from occupational asthma in that it isn't restricted to only occupational exposure, and involves type III hypersensitivity and type IV hypersensitivity rather than the type I hypersensitivity of asthma. Also, unlike asthma, hypersensitivity pneumonitis targets lung alveoli rather than bronchi.

Symptoms of pulmonary fibrosis are mainly:

- Shortness of breath, particularly with exertion

- Chronic dry, hacking coughing

- Fatigue and weakness

- Chest discomfort including chest pain

- Loss of appetite and rapid weight loss

Pulmonary fibrosis is suggested by a history of progressive shortness of breath (dyspnea) with exertion. Sometimes fine inspiratory crackles can be heard at the lung bases on auscultation. A chest x-ray may or may not be abnormal, but high-resolution CT will frequently demonstrate abnormalities.

Asbestosis is long term inflammation and scarring of the lungs due to asbestos. Symptoms may include shortness of breath, cough, wheezing, and chest pain. Complications may include lung cancer, mesothelioma, and pulmonary heart disease.

Asbestosis is caused by breathing in asbestos fibers. Generally it required a relatively large exposure over a long period of time. Such levels of exposure typically only occur in those who work with the material. All types of asbestos fibers are associated with concerns. It is generally recommended that currently existing asbestos be left undisturbed. Diagnosis is based upon a history of exposure together with medical imaging. It is a type of interstitial pulmonary fibrosis.

There is no specific treatment. Recommendations may include stopping smoking, influenza vaccination, pneumococcal vaccination, or oxygen therapy. Asbestosis affected about 157,000 people and resulted in 3,600 deaths in 2015. Asbestos use has been banned in a number of countries in an effort to prevent disease.

Some people with bronchiectasis may have a cough productive of frequent green/yellow mucus (sputum), up to 240 ml (8 oz) daily. Bronchiectasis may also present with coughing up blood (hemoptysis) in the absence of sputum, called "dry bronchiectasis". Sputum production may also occur without coloration. People with bronchiectasis may have bad breath indicative of active infection. Frequent bronchial infections and breathlessness are two possible indicators of bronchiectasis.

Crepitations and expiratory rhonchi may be heard on auscultation. Nail clubbing is rare.

Asthma is an obstructive lung disease where the bronchial tubes (airways) are extra sensitive (hyperresponsive). The airways become inflamed and produce excess mucus and the muscles around the airways tighten making the airways narrower. Asthma is usually triggered by breathing in things in the air such as dust or pollen that produce an allergic reaction. It may be triggered by other things such as an upper respiratory tract infection, cold air, exercise or smoke. Asthma is a common condition and affects over 300 million people around the world.

Asthma causes recurring episodes of wheezing, breathlessness, chest tightness, and coughing, particularly at night or in the early morning.

- Exercise-Induced Asthma — is common in asthmatics, especially after participation in outdoor activities in cold weather.

- Occupational Asthma — An estimated 2% to 5% of all asthma episodes may be caused by exposure to a specific sensitizing agent in the workplace.

- Nocturnal Asthma — is a characteristic problem in poorly controlled asthma and is reported by more than two thirds of sub-optimally treated patients.

A peak flow meter can record variations in the severity of asthma over time. Spirometry, a measurement of lung function, can provide an assessment of the severity, reversibility, and variability of airflow limitation, and help confirm the diagnosis of asthma.

Diagnosis of obstructive disease requires several factors depending on the exact disease being diagnosed. However one commonalty between them is an FEV1/FVC ratio less than 0.7, i.e. the inability to exhale 70% of their breath within one second.

Following is an overview of the main obstructive lung diseases. "Chronic obstructive pulmonary disease" is mainly a combination of chronic bronchitis and emphysema, but may be more or less overlapping with all conditions.