Now, this'll detect levels of carbon monoxide as low as 30 PPM, which is parts per million. To give you a better understanding of what this means, the average carbon monoxide levels in our own homes is anywhere between 0.5, and five ppm.The average carbon monoxide level from a modern vehicle's exhaust is around 1,000 parts per million, and we all know how dangerous vehicle exhaust is. Most people… see more >