In-bus air quality study finds passengers breathe cleaner air for up to 80% of travel time

The country’s in-bus air quality management solution, based on continuous Particulate Matter (PM) monitoring and filtration across 11 IntrCity SmartBus.AQI vehicles found that passengers spent up to 80% of their travel time breathing air with levels below 60 micrograms per cubic meter (μg/m3), which are significantly cleaner than typical winter ambient conditions in many north and central Indian cities.

The analysis of the deployed solution conducted between December 7 and 14, 2025, provides a detailed picture of how Indian passengers are exposed to particulate pollution during long-distance road travel. This represents the first publicly shared evidence on real-time air quality during long-distance travel in India, adding a new dimension to national conversations on mobility and public health.

For most routes, 60-80% of the journey time the PM2.5 lies below 60 μg/m3, indicating generally acceptable air quality conditions during transit. Several bus routes like Delhi-Kanpur, Pune-Nagpur, Pune-Bangalore, Delhi-Lucknow, Pathankot-Delhi, Delhi-Katra, Katra-Delhi has more than 80% of the time PM2.5 levels less than 60 μg/m3. A little high PM2.5 levels were observed in buses transiting on the route of Delhi-Pathankot and Lucknow-Delhi with more than 20% of time exceeding PM2.5 value of 60 μg/m3, according to the analysis.

Even on routes where higher concentrations appear, exposure above 90 μg/m3 is typically limited to a smaller fraction of the journey, often below 10-15% of total travel time for many buses. “This suggests that high-pollution episodes are intermittent rather than sustained, likely driven by short-term external factors such as traffic congestion or localised pollution hotspots,” researchers said.

“This dataset marks a turning point in how we understand air quality during intercity journeys. For the first time, we can quantify what passengers are actually breathing inside buses, identify where risks increase, and highlight where clean-air systems are making a measurable difference,” Ronak Sutaria, founder and CEO of Respirer Living Sciences, said in an official statement released on Thursday.

The study found that, while overall exposure remained moderate for most routes, pollution spikes did occur, but they were short and intermittent. “Pinpointing the specific stretches where exposure spikes allows for targeted interventions, whether through modified ventilation settings, operational adjustments, or improved management of boarding and idling practices during high-pollution hours,” Sutaria added.

The study estimates that, based on the standard 30-seat capacity per bus, nearly 4,500 passenger journeys took place across the monitored buses during the 15-day period. For each of these travellers, the reduced duration of high-pollution exposure translates into a meaningful reduction in respiratory health risks, particularly during peak winter pollution episodes across northern India. “Every clean kilometre matters. We’re not just measuring numbers; we are reducing exposure for thousands of travellers who would otherwise inhale far higher particulate levels,” Sutaria said.

IntrCity SmartBus and Respirer Living Sciences have partnered to launch India’s first air-purified intercity bus fleet — SmartBus.AQI. Respirer’s AI-powered air-quality monitoring and filtration technology has been integrated into select IntrCity buses to continuously monitor and improve cabin air quality, targeting pollutants such as PM2.5, carbon dioxide, dust, and smoke.

“Passengers can view real-time AQI and PM2.5 data onboard and through the IntrCity app, bringing unprecedented transparency to in-transit air quality. The initiative addresses evidence from internal tests showing that in-bus pollution levels can be two to three times higher than safe limits, prompting this collaboration to deploy cleaner air systems on high-pollution routes,” Manish Rathi, CEO and CoFounder, IntrCity added.