Product: Awair Omni, Awair Element, Awair Score

Overview

Indoor Air Quality (IAQ) is critical for ensuring healthy and comfortable environments. Our IAQ Score System, utilizing advanced sensor technology, provides a comprehensive and nuanced assessment of air quality within indoor spaces. This white paper outlines the updated scoring system that improves upon our previous methodology, emphasizing health-based factors over comfort-based ones. Feel free to skip ahead using the bookmark links below:

Overview of the IAQ Score System

The IAQ Score System integrates readings from five sensors: Temperature, Humidity, Volatile Organic Compounds (VOC), Carbon Dioxide (CO2), and Particulate Matter (PM2.5). The system evaluates these parameters to generate an overall air quality score, reflecting both comfort and health considerations. To gain a better understanding of the Awair Score and Air Factors sensed by our devices, please check out our resources for the Awair Omni and Awair Element.

Old Scoring System

In the previous system, each factor contributed equally (approximately 20%) to the total score. However, this approach had limitations. For instance, a high CO2 level significantly impacting air quality would only reduce the overall score marginally, potentially misleading users about the severity of the air quality issues.

Updated Scoring System

The new system categorizes sensors into two groups:

Comfort-Based Sensors: Temperature and Humidity
Health-Based Sensors: VOC, CO2, and PM2.5

Health-based factors now have more weight in the scoring, addressing the prior system's shortcomings.

Scoring Methodology

The new air quality scoring system begins with normalizing sensor data to a scale where 0 represents good quality and 1 indicates the worst, assigning values to color-coded buckets that correspond to a range of scores. For example, a CO2 level well above the healthy range may be normalized to 0.5 and categorized as orange. Penalties are then introduced for severe or combined unhealthy sensor readings, calculated using an exponential formula which takes into account the severity and the number of sensors in the more critical buckets. Specifically, if multiple important sensors like VOC, CO2, and PM2.5 register poor readings, a penalty is applied. Additionally, extreme temperature and humidity readings incur extra penalties. The final Indoor Air Quality (IAQ) score is a composite of the highest normalized values from CO2, VOC, and PM2.5 readings. Additionally, it incorporates penalty calculations based on research and extensive laboratory testing.

Experimental Results and Graphical Representations

1. Experiment with VOC readings:

Experiment with different VOC levels with Scoring System

The above experiment was conducted to compare the legacy scoring system with the new scoring system reflecting the changes in indoor air quality as influenced by the concentration of volatile organic compounds (VOCs). The study's impetus was to evaluate the efficacy of the new scoring metric, which purports to better represent the harmful effects of VOCs, as outlined by the World Health Organization's guidelines. In a controlled experimental setup, continuous monitoring of VOC levels was conducted, with data logged at five-minute intervals over a span of two hours. It was observed that the 'Old Score' remained relatively unchanged until VOC levels surpassed the 3000 ppb threshold, whereas the 'New Score' promptly declined in response to VOC increments above 100 ppb, exhibiting a heightened sensitivity to VOC variations. This acute response aligns with the design objective of the 'New Score', offering a real-time indication of air quality and potential health risks. The most significant data point was the 'New Score's sharp fall from the 70-80 (Good) range to the 30-40 (Poor) range when VOC readings peaked, emphasizing its capability to signal an immediate health hazard. The findings corroborate the hypothesis that the 'New Score' provides a more accurate and immediate reflection of air quality, highlighting its utility in environmental health monitoring and risk assessment. The report based on the above experimental data concludes with a recommendation for the adoption of the 'New Score' for more responsive and preventative indoor air quality management.

2. Experiment with all sensor readings:

Sensor readings from CO2, VOC, PM2.5, TEMP, HUMIDITY after office hours

The purpose of this test was to deploy our devices in an actual office setting to monitor and verify that the scores accurately reflect the real-time air quality. We observed that the air quality measurements, particularly CO2 and TVOC levels, improved notably after office hours as shown in the image above. Initially, due to elevated CO2 and TVOC levels, the air quality score was approximately 50, indicating moderate conditions. However, with the subsequent improvements in these readings, the score increased to the 70s, signifying that the air quality had reached an acceptable level. This progression aligns with our established scoring criteria, as demonstrated in the image below.

Awair Score Index

score reading going down.png

Sensor readings from CO2, VOC, PM2.5, TEMP, HUMIDITY starting office hours

The experiment was extended to include the period up until the following day when office hours resumed. Overnight, there was a noticeable improvement in sensor readings, which resulted in an increased score, starting at 80, indicating good air quality. However, as the day progressed, temperature and humidity levels reached moderate levels, represented by the orange color, while CO2 and VOC levels deteriorated from good to poor, as shown by the transition from green to orange in the image above. This decline brought the overall air quality score down to 40, categorized as poor, which accurately reflected the worsening condition of the air quality.

air purifier.png

Sensor readings from CO2, VOC, PM2.5, TEMP, HUMIDITY after turning on the Air Purifier

The sensors consistently recorded high levels of pollutants, maintaining the score in the 40s. This persistent poor air quality signaled the need for intervention. Accordingly, at 11:40, an air purifier was activated to enhance the indoor air quality. This action had a positive effect, as evidenced by the improved sensor readings, which in turn raised the total score back up to 80, indicating good air quality.

The results of this experiment confirm that the new scoring system effectively mirrors the changes in indoor air quality and provides timely indications for users to take necessary measures to improve their environment.

Conclusion

The updated IAQ Score System offers a more accurate and health-conscious assessment of indoor air quality. By refining the weightage of different sensors and introducing a nuanced penalty system, the system ensures that users are well-informed about the air quality in their surroundings, facilitating better decision-making for health and comfort.

Citations and Standards

OSHA and EPA: For Temperature and Humidity standards.
WHO and EPA: For VOC standards.
ASHRAE: For CO2 standards.
WELL/RESET: For VOC standards.

These references ensure that our scoring system aligns with recognized health and safety standards.