  Jupiter-family Comets (JFCs) exhibit a wide range of activity levels and
mass-loss over their orbits. We analyzed high-cadence observations of 42 active
JFCs with the wide-field Asteroid Terrestrial-impact Last Alert System (ATLAS)
survey in 2020-2021. We measured dust production rates of the JFCs using the
Af\rho parameter and its variation as a function of heliocentric distance.
There is a tendency for our JFC sample to exhibit a maximum Af\rho after
perihelion, with 254P/McNaught and P/2020 WJ5 (Lemmon) having their maximum
Af\rho over a year after perihelion. On average, the rate of change of activity
post-perihelion was shallower than that pre-perihelion. We also estimated the
mass maximum loss rate for 17 of the JFCs in our sample, finding 4P/Faye to be
the most active. We present a subset of comets whose measured Af\rho have been
interpolated and extrapolated to a common distance of 2 au pre-perihelion and
post-perihelion. From these measurements we found no correlation of intrinsic
activity with current perihelion distance. For three of the JFCs in our sample,
6P/d'Arrest, 156P/Russell-LINEAR and 254P/McNaught, there was no visible coma
but a constant absolute magnitude which we attributed to a probable detection
of the nucleus. We derived upper limits for the nuclear radii of \leq 2.1 +/-
0.3 km, \leq 2.0 +/- 0.2 km and \leq 4.0 +/- 0.8 km respectively. Finally, we
found that 4P/Faye, 108P/Ciffreo, 132P/Helin-Roman-Alu 2, 141P/Machholz 2, and
398P/Boattini experienced outbursts between 2020 and 2022.
