A low-maintenance optoacoustic sensor for black carbon monitoring

Abstract. Regulation of black carbon (BC) emissions is necessary due to their negative impact to climate and human health. We present a low-cost optoacoustic sensor for Black Carbon (BC) emissions, which can provide continuous measurements that are suitable for long-term BC monitoring in highly contaminative environments with low need for frequent maintenance. Insensitivity to contamination is based on a sensor design that integrates protective flows of clean air around the sample measured, which minimizes BC deposition on the detector and optical windows of the sensor. A quantitative analysis shows that the negative effect of BC contamination on sensor performance is reduced by a factor of greater than 300 000 in comparison to an unprotected control sensor. We discuss how the reduced maintenance requirements make the design presented a promising candidate for continuous and long-term BC monitoring of high emitters, enabling disseminated monitoring necessary for regulatory and mitigation measures of BC emissions in the future.