Within a home or building, common sources of irritation include:
- Physical pollutants like dust
- Biological pollutants like mold or dander
- Chemical pollutants like volatile organic compounds (VOCs) from some solvents
Additional sources of irritants within a building may include:
- Personal care products
- Pesticides
- Cleaning and air deodorizing products
- Furnishings
Some sources may linger and remain in a room or building when ventilation is poor. This is especially true for:
- Glues
- Fragrances
- Materials off-gassing from pressed-wood furnishings
- Permanent-press fabrics like curtains
While ventilation is important in diluting and removing typical indoor pollutants, the best indoor air practice is to reduce or eliminate the use of materials that cause irritation. For example, stopping the use of air deodorizing products that mask odors can prevent respiratory irritation.
What are some types of irritant sources?
Particulate matter
Particles in the air can affect indoor air quality. PM2.5 refers to fine liquid or solid particles that are 2.5 microns in diameter or less. Because of their small size, PM2.5 can penetrate deep into the lungs and get into the bloodstream. PM2.5 can worsen pre-existing respiratory conditions, such as asthma. Children are particularly sensitive to particulate matter since they breathe more air per pound of body weight than adults.
Indoor sources of PM2.5 can include:
- Pet dander
- Bacteria
- Mold
- Chemicals from cleaning products
- Building materials
- Candles
- Fuel burning equipment like furnaces
- Upholstered goods
- Cooking
- Sweeping
- Discharge from kilns and copy machines
Outdoor PM2.5 sources, such as vehicle exhaust and tobacco smoke, often enter a building and contribute to the particulates within a building.
Whether the source is indoors or outdoors, it is important to reduce indoor particulate pollutants.
- Limit the use of products like air deodorizers to reduce sources of particles in the indoor environment
- Use localized exhaust ventilation during cooking or copying, as well as servicing, maintaining, and changing filters on heating and cooling equipment to remove or dilute indoor PM2.5
- Clean surfaces using a wet wipe, microfiber cloth, or HEPA-filtered vacuum to prevent settled particles from being recirculated
- Use doormats at entry points to reduce dust tracked into the home
- Close windows when high levels of pollen or particles are forecasted to prevent particles from getting indoors
Volatile organic compounds
Volatile organic compounds (VOCs) are gases emitted or off-gassed from items like cleaning products, building materials, and furnishings.
VOCs are commonly released indoors when:
- Cleaning products are sprayed or applied
- Air deodorizers are installed
- Personal care products like perfumes and colognes are used
- New furnishings are brought in
- Walls are painted
Indoor concentrations of many VOCs are typically higher than outdoors. Ventilation can help to lower indoor levels of VOCs. Limiting the use of these products can reduce the potential for allergies and other adverse health effects.
Indoor air quality in public buildings
During an assessment of a school or public building, DPH Indoor Air Quality Outreach and Education Unit (IAQ) staff take measurements and make observations to identify processes or products that can contribute to respirable particles or cause off-gassing of VOCs. Staff measure PM2.5 levels in each area to help determine if ventilation is working to remove respirable dusts. Staff also note processes or products that may contribute to PM2.5 indoors, such as metalwork, wood cutting, or clay art drying in kilns.
There are currently no government standards for indoor PM2.5 concentrations. However, DPH uses the U.S. Environmental Protection Agency’s (EPA) National Ambient Air Quality Standard (NAAQS) of 35 µg/m3 (a 24-hour limit) to evaluate indoor PM2.5 levels. Frequently, indoor air particulate levels (including PM2.5) can be higher than those measured outdoors.
Additionally, DPH IAQ Unit staff identify whether VOC-containing products are present in a classroom or office. These products can include cleaners, deodorizers, and dry erase materials. Indicating the presence of these products can help school staff work towards reducing the number of irritant products within their school.