How to manage exposure to high levels of particulate matter (PM) air pollution?

Managing Exposure to High Levels of Particulate Matter (PM) Air Pollution

The most effective strategy to reduce health risks from PM air pollution is wearing properly fitted N95, KN95, or FFP2 respirators when PM concentrations are high, combined with using HEPA air purifiers in bedrooms and living rooms where people spend most time. 1, 2

Immediate Personal Protection Strategies

Respiratory Protection

• N95, KN95, or FFP2 respirators provide the strongest protection, reducing PM2.5 exposure by more than 14-fold when worn with proper fit (5% leak rate or less), and can remove 14-96% of particulate matter depending on correct use 1, 2
• Masks should be worn whenever local PM concentrations are elevated, particularly during pollution peaks 1, 2
• Important caveat: Wearing masks can cause dyspnea in high temperatures, especially during physical activity 1
• Masks also provide the added benefit of reducing respiratory virus transmission, which is particularly important since air pollution increases susceptibility to respiratory infections 1

Timing and Location Modifications

• Avoid outdoor activities during peak pollution hours: PM and NO2 levels are typically highest during rush hours, while ozone (O3) peaks in the afternoon and early evening 1
• Exercise in the morning when pollutant levels are lower 1
• Reduce exercise intensity or relocate activities indoors when PM concentrations are high 1
• Maximize time in less polluted locations: parks, green and blue spaces when PM or NO2 is high; indoor well-ventilated modern spaces with closed windows when O3 is high 1

Indoor Air Quality Management

HEPA Air Purification

• Home air purifiers with HEPA filters substantially reduce indoor PM exposure and provide measurable cardiopulmonary benefits 2
• Indoor air pollutant levels are typically 2-5 times higher than outdoor levels, making indoor air purification particularly important 2
• Place air purifiers in bedrooms and living rooms where people spend the most time 2
• Air purification reduces multiple adverse health outcomes including respiratory illness, allergic symptoms, cancers, and premature mortality 2
• Evidence shows short-term use of portable HEPA filtration systems reduced personal PM2.5 exposures and systolic blood pressure by 3.2 mm Hg among older adults 3

Indoor Source Control

• Close vehicle windows, use cabin filters, and turn on air-conditioning during transport through polluted areas 1
• Address indoor combustion sources: gas stoves regularly exceed WHO daily NO2 guideline values of 25 μg/m³, with current EU outdoor hourly limits of 200 μg/m³ NO2 exceeded indoors multiple times weekly in typical European households using gas for cooking 1
• Use range hoods ducted to the outside when cooking with gas, as they effectively reduce harmful pollutant concentrations when used correctly 1
• Ensure proper ventilation and maintenance of all combustion appliances 1

Transportation Strategies

Route and Mode Planning

• Plan journeys (time and route) in advance to minimize time in areas with poor air quality 1
• Limit time spent in confined spaces and overcrowded areas such as buses, subways, and metro stations where PM concentrations are particularly high 1
• Favor low-emission transportation options when possible 1

Respiratory Health Protection

Preventive Measures for High-Risk Individuals

• Those with asthma, COPD, or exercise-induced bronchoconstriction are more sensitive to pollutant effects and require heightened precautions 1
• Practice physical distancing, hand washing, use alcohol-based hand sanitizer, and consider face masking to limit acute respiratory illness that can be exacerbated by air pollution 1
• Ensure up-to-date vaccinations before traveling to areas with high pollution 1

Nutritional Considerations

• Consider consuming antioxidant supplementation: vitamin C (250-600 mg), vitamin E (75-100 mg), and beta carotene (25 mg) the week before high-exposure events, though evidence for this strategy remains limited 1

Monitoring and Communication

Real-Time Air Quality Tracking

• Monitor air quality forecasts and real-time assessments using local monitoring stations or low-cost wearable air pollution sensors 1
• Follow WHO guidelines for PM and O3 concentrations to determine when to implement protective measures 1
• Pay particular attention to location-specific pollution levels, as PM concentrations can vary dramatically even within short distances 1

Critical Context

Poor indoor air quality remains the most influential risk factor for respiratory disease in housing environments, confirmed by a review of 360 studies 2. Anthropogenic PM2.5 was responsible for 107,000 premature deaths in the United States in 2011, with 57% associated with energy consumption (transportation 28%, electricity generation 14%) and 15% with agricultural activities 4. The health and economic burden is substantial, estimated at $886 billion annually 4.

Air pollution mechanistically reduces oxygen delivery to tissues, increases oxidative stress and inflammation, and increases respiratory symptoms including asthma exacerbations, lung inflammation, and nose and throat irritation 1. It also increases the risk and severity of respiratory virus infections 1.