Methods of atmospheric air research

Major chemical pollutants and their effects

During hygienic monitoring of the air environment, special attention is paid to a number of highly toxic chemical compounds that enter the atmosphere as a result of industrial activities, fuel combustion, and internal combustion engine operation.

• Carbon monoxide (CO). It enters via inhalation and firmly binds to hemoglobin, forming carboxyhemoglobin. This blocks oxygen transport to tissues, causing acute or chronic anoxemia (hypoxia). Chronic exposure manifests as headaches, fatigue, and sleep disturbances.
• Sulfur dioxide (SO₂). Formed during the combustion of coal and high-sulfur fuel oil. It has a powerful irritating effect on the mucous membranes of the respiratory tract and eyes, provoking chronic bronchitis and conjunctivitis. In the atmosphere, it oxidizes and, combining with moisture, forms sulfuric acid aerosol.
• Nitrogen oxides (especially NO₂). The main source is motor transport and the chemical industry. In the blood, NO₂ converts hemoglobin into methemoglobin, which also leads to tissue hypoxia. Prolonged inhalation exacerbates the course of cardiovascular pathologies and causes anemia.
• Carcinogenic hydrocarbons. Represented by polycyclic aromatic hydrocarbons (PAHs), the leader among which is 3,4-benzopyrene. A direct link has been proven between its concentration in the air and the incidence of bronchopulmonary cancer among urban residents.

Mechanical impurities (atmospheric dust)

Dust consists of solid particles suspended in the air of natural (cosmic, soil, plant) and artificial (industrial) origin.

Artificial dust generated during fuel combustion poses the greatest hygienic hazard. It consists of ash, unburned particles (soot residue), and soot. Soot is the most pathogenic element as it adsorbs carcinogens (anthracene, methylcholanthrene) on its surface.

Dust has a dual impact on health:

1. Indirect. It reduces solar radiation intensity and promotes fog formation. Insufficient insolation leads to rickets in children, osteoporosis in adults, and increases the survival rate of pathogenic microflora.
2. Direct. It exerts toxic, allergenic, fibrogenic (development of pneumoconiosis), and irritating effects on tissues.

Global consequences of atmospheric pollution

The accumulation of pollutants in the air basin goes beyond local problems and provokes large-scale ecological shifts:

• Acid rain. Sulfur and nitrogen dioxides interact with water vapor, forming sulfuric and nitric acids. Rainwater with a pH from 6.0 to 4.0 is disastrous for the biosphere: aquatic ecosystems are destroyed, forests die, crop yields drop, and architectural monuments corrode.
• Greenhouse effect. Excess carbon dioxide and methane act like glass, trapping the Earth's thermal radiation. This threatens global warming (by 0.5 °C every 10 years), ice melting, rising sea levels, and flooding of coastal zones.
• Ozone layer depletion. Chlorofluorocarbons (CFCs), under the action of ultraviolet radiation, release chlorine and bromine atoms, which break down triatomic ozone molecules in a chain reaction. The loss of the ozone shield is fraught with a surge in skin cancer, an increase in cataracts, and global immune suppression.
• Smogs (toxic fogs). Formed during temperature inversions (when upper air layers are warmer than ground-level ones), calm weather, and high humidity. A sharp accumulation of sulfur dioxide and sulfuric acid occurs, which drastically increases mortality among children and the elderly. A special type is photochemical smog, which occurs in dry, sunny weather due to the interaction of exhaust gases (nitrogen oxides and hydrocarbons) under the influence of ultraviolet light.

Principles of air sanitary protection

Natural self-purification of the atmosphere (dust sedimentation, washout by precipitation, wind dilution) does not compensate for the anthropogenic load. Therefore, strict protection measures are applied, based on regulatory acts (Federal Law-52, SanPiN).

The basic safety criterion is the maximum permissible concentration (MPC). This is the concentration of a substance in mg/m³ that, when exposed to throughout life, causes no harm to health and offspring, and does not reduce working capacity. Maximum single MPC (for substances with a pungent odor) and general toxic daily average MPC are distinguished.

Air protection measures include:

• Planning: proper zoning taking into account the wind rose, landscaping, creation of sanitary-protective zones (SPZs). The SPZ separates industrial facilities from residential areas, acting as a filter and architectural barrier.
• Technological: transition to eco-friendly fuels, electrification, modernization of treatment facilities.

Briefly: answers to topical questions

Class and exam questions

What else to study on this topic

• Toxicodynamics of carbon monoxide and pathogenesis of carboxyhemoglobin formation
• Chemistry of photochemical reactions: the role of nitrogen oxides and hydrocarbons
• Ecological consequences of acid rain for the hydrosphere and lithosphere
• Impact of chlorofluorocarbons (CFCs) on the ozone layer: decay mechanism
• Sanitary and hygienic functions of green spaces in SPZs

Other topics in "Chapter 1. Ecological and hygienic problems of atmospheric air"

Prepared by WhiteCoat Pro faculty in accordance with the medical school curriculum. For educational purposes only.