9 - Critical Air Pollutants (CAPS)

• Air pollution involves alterations to atmospheric air's physical, chemical, and biological properties, potentially harming public health and the environment
• Critical and hazardous pollutants are major categories of air pollutants.
• Air pollution can cause minor irritations, severe chronic conditions, cancer, or death.

Critical Air Pollutants (CAPS)

• These are widespread, emitted from diverse sources, and pose a higher risk.
• Mobile sources like vehicle emissions and stationary sources such as factories are included.
• They are not very toxic but constantly present, posing the greatest threat to human health.
• Respiratory tract irritations and aggravation of pre-existing respiratory diseases (e.g., asthma) occur.
• Suspended particulate matter like TSP, PM2.5, and PM10 are measured using DENR guidelines.
• PM2.5 is potentially carcinogenic and can deposit deep in the respiratory system.
• PM10, a coarse particulate matter, gets trapped in the nasopharyngeal region.
• Sulfur dioxide comes from volcanoes, vehicles, and power plants.
• Nitrogen dioxide is from vehicle emissions.
• Photochemical oxidants like tropospheric ozone form via atmospheric photochemical reactions.
• Carbon monoxide is emitted from vehicles and fireplaces

Hazardous Air Pollutants (HAPS)

• HAPS sources are limited and industry-specific while being more hazardous than CAPS
• Examples include benzene, formaldehyde, cadmium, and vinyl chloride.
• National Emission Standards for Site-Specific Air Pollutants (NESA) regulate outdoor pollutants, while Occupational Safety and Health Standards oversee indoor pollutants.

Health Impacts

• Eye irritation can be specifically caused by photochemical oxidants (e.g., ozone), aldehydes, and particulate matter.
• Pathogenic bio-aerosols, like SARS-CoV-2, increase the risk of acute respiratory infections, particularly in young children.
• Acute bronchitis can be induced by the direct irritating effects of SO2.

Environmental Impacts

• Air pollution has an impact beyond just human health.

Global Warming

• It is caused by the accumulation of greenhouse gases such as water vapor, carbon dioxide, methane, ozone, and nitrous oxide.
• Greenhouse gases trap heat, increasing atmospheric temperature, and have severe environmental consequences.

Acid Rain

• Acid rain is caused by nitrogen dioxide (NO₂) transforming into nitric acid (HNO3), along with sulfur dioxide (SO₂) converting into sulfuric acid (H2SO4).

Agencies for monitoring air pollution

• DENR monitors TSP, PM10, NO2, SO2, and O3.
• The PNRI monitors PM10 and PM2.5 using the Gent sampler at three sites in Metro Manila.
• The Manila Observatory monitors PM2.5 using air samplers on New Year's Eve since 2003 in Metro Manila.

Monitoring Methods

• Direct reading measurements involve using tools like detector tube pumps, toxic gas detectors, and light scattering monitors.
• Indirect/Integrated Sampling
  • It requires laboratory analysis after collection.
  • Includes active and passive sampling techniques

Pollutant Control Methods

• Control involves legislative measures like the Philippine Clean Air Act of 1999.
• Enclosure/isolation separates the source from the worker.
• Local exhaust ventilation uses laboratory hoods and paint spray booths.
• General ventilation involves open windows and HVAC systems.
• Housekeeping minimizes contaminant dissemination through surface and spill clean-up.
• Personal protective equipment includes respirators; work practices minimize contaminant spread.