Is it safe to participate in a race when the Air Quality Index (AQI) is 120?

Racing at AQI 120 Carries Significant Health Risks and Should Be Avoided or Modified

Racing at an Air Quality Index (AQI) of 120 is not safe and should be avoided, particularly for endurance events, or at minimum require substantial modifications to reduce exposure and intensity. An AQI of 120 falls into the "unhealthy for sensitive groups" category, and the evidence clearly demonstrates that air pollution at these levels impairs athletic performance and poses cardiopulmonary health risks, especially during high-intensity exercise 1.

Understanding the Risk at AQI 120

An AQI of 120 represents moderate to unhealthy air quality conditions. The available evidence shows that:

• Performance impairment occurs even at lower levels: Athletes exposed to pollutant levels well below AQI 120 (even within "good-to-moderate" classifications) experience measurable performance decrements 2, 3, 4
• Dose-response relationship exists: Higher pollution concentrations produce more severe negative effects, and this is amplified during exercise due to increased minute ventilation 1
• Endurance athletes are particularly vulnerable: Those participating in races (especially endurance events) show heightened susceptibility to air pollution effects, even at low concentrations 1

Specific Health Concerns

Air pollution exposure during racing at AQI 120 can cause:

• Reduced oxygen delivery to tissues
• Increased oxidative stress and inflammation
• Respiratory symptoms including asthma exacerbation, lung inflammation, nose and throat irritation 1
• Eye discomfort and skin sensitivity
• Increased risk of respiratory infections due to compromised immunity 1

Athletes with exercise-induced bronchoconstriction or pre-existing asthma face even greater risks 1.

Risk Stratification: Who Should Absolutely Not Race

High-risk individuals who should not participate:

• Athletes with exercise-induced bronchoconstriction
• Those with asthma or chronic lung disease
• Individuals with cardiovascular disease
• Endurance athletes (particularly susceptible even at low pollution levels) 1

Moderate-risk individuals who require significant modifications:

• Recreational athletes without pre-existing conditions
• Younger athletes (18-29 years show larger performance decrements) 4

If You Must Race: Mitigation Strategies

If postponement or relocation is impossible, implement these evidence-based modifications 1:

Timing Modifications

• Avoid afternoon and early evening when ozone peaks are highest
• Race in early morning when pollutant levels are typically lower

Intensity Modifications

• Reduce race intensity to decrease total inhaled pollutant dose
• Consider this a training effort rather than a competitive race
• Monitor for respiratory symptoms and be prepared to stop

Protective Measures

• Wear an N95, KN95, or FFP2 mask before and after the race (not during, as this impairs breathing during high-intensity exercise)
• Minimize time outdoors before and after the event
• Use air-conditioned transport with cabin filters and closed windows 1

Pre-Race Preparation

If you have 4-7 days before the race and live in cleaner air, consider that acclimatization to pollution may provide minimal benefit and is not well-studied in athletes with asthma 1

Nutritional Strategies

Consider antioxidant supplementation in the week before:

• Vitamin C: 250-600 mg
• Vitamin E: 75-100 mg
• Beta carotene: 25 mg 1

(Note: Evidence for these interventions is limited)

The Performance Impact

Real-world data demonstrates measurable performance decrements:

• Marathon runners show 1.43-1.56 minutes slower per 1 µg/m³ increase in NO₂ 4
• Collegiate runners exposed to elevated PM2.5 and ozone during training showed 11-13 second increases in race times 2
• Recreational runners experience effects 6-fold larger than elite athletes (though elites are still affected) 4
• Thoroughbred racehorses showed decreased winning speeds with pre-competition pollution exposure 3

Common Pitfalls to Avoid

1. Don't assume you're not affected because you "feel fine": Performance decrements occur even without obvious symptoms
2. Don't rely on the standard AQI activity recommendations: These are designed for general population health, not athletic performance, and may not be sufficiently protective 5
3. Don't think indoor warm-up protects you: The race itself involves sustained high-intensity breathing of polluted air
4. Don't ignore cumulative exposure: Training in polluted air for days before the race compounds the effect 2, 3

The Bottom Line

The safest recommendation is to postpone, relocate, or cancel participation in races when AQI reaches 120. The evidence from multiple high-quality 2024 guidelines 1 and recent research 2, 3, 4 consistently demonstrates that air pollution at these levels impairs both health and performance during athletic competition. While mitigation strategies can reduce risk, they cannot eliminate it, and the dose-response relationship means that racing at AQI 120 involves accepting measurable health risks and performance impairment that would not occur in cleaner air.