Seasonal and diel variations of ammonia and methane emissions from a naturally ventilated dairy building and the associated factors influencing emissions C.K. Saha a,c, ⁎, C. Ammon a , W. Berg a , M. Fiedler a , C. Loebsin b , P. Sanftleben b , R. Brunsch a , T. Amon a a Leibniz Institute for Agricultural Engineering Potsdam-Bornim (ATB), Department of Engineering for Livestock Management, Max-Eyth-Allee 100, 14469 Potsdam, Germany b State Institute for Agriculture and Fishery MV, Institute of Animal Production, Wilhelm-Stahl-Allee 2, 18196 Dummerstorf, Germany c Department of Farm Power and Machinery, Bangladesh Agricultural University, Mymensingh 2202, Bangladesh HIGHLIGHTS • Ammonia (NH 3 ) emission was varied seasonally following in and outside temperature. • Methane (CH 4 ) emission did not show clear seasonal trend. • Diel variation of CH 4 emission was less pronounced than NH 3 emission. • Temperature, humidity, wind and time of the day significantly affected NH 3 emissions. • Sine and cosine of the circular variables improved dynamic nature of the models. abstract article info Article history: Received 10 June 2013 Received in revised form 5 August 2013 Accepted 7 August 2013 Available online 6 September 2013 Editor: Xuexi Tie Keywords: Seasonal Air change rate Natural ventilation Emission Modelling Understanding seasonal and diel variations of ammonia (NH 3 ) and methane (CH 4 ) emissions from a naturally ventilated dairy (NVD) building may lead to develop successful control strategies for reducing emissions throughout the year. The main objective of this study was to quantify seasonal and diel variations of NH 3 and CH 4 emissions together with associated factors influencing emissions. Measurements were carried out with iden- tical experimental set-up to cover three winter, spring and summer seasons, and two autumn seasons in the years 2010, 2011, and 2012. The data from 2010 and 2011 were used for developing emission prediction models and the data from 2012 were used for model validation. The results showed that NH 3 emission varied seasonally following outside temperature whereas CH 4 emission did not show clear seasonal trend. Diel variation of CH 4 emission was less pronounced than NH 3 . The average NH 3 and CH 4 emissions between 6 a.m. and 6 p.m. were 66% and 33% higher than the average NH 3 and CH 4 emissions between 6 p.m. and 6 a.m., respectively for all sea- sons. The significant relationships (P b 0.0001) between NH 3 and influencing factors were found including out- side temperature, humidity, wind speed and direction, hour of the day and day of the year. The significant effect (P b 0.0001) of climate factors, hours of the day and days of the year on CH 4 emission might be directly related to activities of the cows. © 2013 Elsevier B.V. All rights reserved. 1. Introduction Emissions of ammonia (NH 3 ) and greenhouse gases, e.g. methane (CH 4 ) and nitrous oxide (N 2 O), from livestock production systems are of great concern to livestock producers, environmentalists, and govern- ments due to their negative impact on surrounding environment and global climate (Bull and Sutton, 1998; IPCC, 2001). Dairy cow farming is one of the largest sources of NH 3 and CH 4 within livestock production (FAO, 2006). Emissions from dairy cow production systems need to be reduced to limit environmental problems associated with livestock. Due to this fact, it is very important to understand seasonal and diel var- iations of NH 3 and CH 4 emissions from naturally ventilated dairy (NVD) buildings together with factors affecting these variations and emissions. These understandings may lead to the development of successful con- trol strategies of emissions throughout the year according to the need of environmentalists and governments. The emission from an NVD building directly depends on atmospher- ic influences under continuously changing conditions (Ngwabie et al., 2011; Snell et al., 2003). Several researches have been carried out to identify management and climate related factors influencing air change per hour (ACH) and emissions. Through their review, Monteny and Science of the Total Environment 468–469 (2014) 53–62 ⁎ Corresponding author at: Leibniz Institute for Agricultural Engineering Potsdam- Bornim (ATB), Department of Engineering for Livestock Management, Max-Eyth-Allee 100, 14469 Potsdam, Germany. Tel.: +49 331 569 9518. E-mail addresses: csaha@atb-potsdam.de, cksahabau@yahoo.com (C.K. Saha). 0048-9697/$ – see front matter © 2013 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.scitotenv.2013.08.015 Contents lists available at ScienceDirect Science of the Total Environment journal homepage: www.elsevier.com/locate/scitotenv